Fibrotic Burden in the Liver Differs Across Metabolic Dysfunction-Associated Fatty Liver Disease Subtypes

Lim Tae Seop,Chun Ho Soo,Kim Soon Sun,Kim Ja Kyung,Lee Minjong,Cho Hyo Jung,Kim Seung Up,Cheong Jae Youn 거트앤리버 소화기연관학회협의회 2023 Gut and Liver Vol.17 No.4

Background/Aims: Metabolic dysfunction-associated fatty liver disease (MAFLD) is categorized into three subtypes: overweight/obese (OW), lean/normal weight with metabolic abnormalities, and diabetes mellitus (DM). We investigated whether fibrotic burden in liver differs across subtypes of MAFLD patients. Methods: This cross-sectional multicenter study was done in cohorts of subjects who underwent a comprehensive medical health checkup between January 2014 and December 2020. A total of 42,651 patients with ultrasound-diagnosed fatty liver were included. Patients were classified as no MAFLD, OW-MAFLD, lean-MAFLD, and DM-MAFLD. Advanced liver fibrosis was defined based on the nonalcoholic fatty liver disease fibrosis score (NFS) or fibrosis-4 (FIB-4) index. Results: The mean age of the patients was 50.0 years, and 74.1% were male. The proportion of patients with NFS-defined advanced liver fibrosis was the highest in DM-MAFLD (6.6%), followed by OW-MAFLD (2.0%), lean-MAFLD (1.3%), and no MAFLD (0.2%). The proportion of patients with FIB-4-defined advanced liver fibrosis was the highest in DM-MAFLD (8.6%), followed by lean-MAFLD (3.9%), OW-MAFLD (3.0%), and no MAFLD (2.0%). With the no MAFLD group as reference, the adjusted odds ratios (95% confidence intervals) for NFS-defined advanced liver fibrosis were 4.46 (2.09 to 9.51), 2.81 (1.12 to 6.39), and 9.52 (4.46 to 20.36) in OW-MAFLD, lean- MAFLD, and DM-MAFLD, respectively, and the adjusted odds ratios for FIB-4-defined advanced liver fibrosis were 1.03 (0.78 to 1.36), 1.14 (0.82 to 1.57), and 1.97 (1.48 to 2.62) in OW-MAFLD, lean-MAFLD, and DM-MAFLD. Conclusions: Fibrotic burden in the liver differs across MAFLD subtypes. Optimized surveillance strategies and therapeutic options might be needed for different MAFLD subtypes.

Design of High Efficiency Wound Field Synchronous Machine With Winding Connection Change Method

Lim, Myung-Seop,Hong, Jung-Pyo IEEE 2018 IEEE transactions on energy conversion Vol.33 No.4

<P>In this paper, a design method for a wound field synchronous motor (WFSM) employing the dual stator winding and the winding connection change circuit is proposed. Through the design method, the WFSM can be operated as two different modes, and each mode is determined by the connection between the stator windings U, V, W and X, Y, Z. By applying the proposed method to the conventional WFSM, the operation mode of the motor is changed at a certain speed. The speed for the mode change is determined to maximize the efficiency of the machine. As a result, through the mode change, the line to line induced voltage, current phase angle, and phase resistance are decreased. In addition, the demand field current is also reduced to achieve the required torque due to the salient pole characteristics of WFSM. Consequently, the efficiency of the WFSM is increased due to the mode change. Finally, the effect of the proposed method and the validity of the simulation results are verified by the load test.</P>

Design of an Ultra-High-Speed Permanent-Magnet Motor for an Electric Turbocharger Considering Speed Response Characteristics

Lim, Myung-Seop,Kim, Ji-Min,Hwang, Yong-Suk,Hong, Jung-Pyo Institute of Electrical and Electronics Engineers 2017 IEEE/ASME Transactions on Mechatronics Vol. No.

<P>This paper presents a design methodology and analysis for a 4-kW 150-krpm ultra-high-speed surfacemounted permanent-magnet synchronous motor (SPMSM) to electrically assist a turbocharger. The proposed design methodology is aimed at achieving a required torque and speed. In addition, this study seeks a fast-speed response as a design objective to eliminate turbo lagmore effectively. First, an existing prototype that does not meet the target performance is presented. The loss for the prototype, which is difficult to obtain theoretically, is obtained experimentally and reflected in the design. The speed response characteristic of the machine is analyzed through the electromechanical undamped natural frequency and damping ratio. Design parameters such as the permanent-magnet (PM) grade, the turn number of coils, and the axial length of the motor are designed. The resulting improved motor achieves higher power density as well as faster speed response than the prototype. Experiments verified the effectiveness of the motor in the electrically assisted turbocharger. In system experiments with the turbocharger, the rising speed of the boost pressure is improved by 44.9% due to the designed motor.</P>

Experimental Characterization of the Slinky-Laminated Core and Iron Loss Analysis of Electrical Machine

Lim, Myung-Seop,Kim, Ji-Hyun,Hong, Jung-Pyo IEEE 2015 IEEE transactions on magnetics Vol.51 No.11

<P>The magnetic properties of a motor core deteriorate during the manufacturing process due to mechanical stresses in the materials. It is particularly hard to predict the characteristics of the slinky-laminated electrical machines, because stresses and strains occur simultaneously in the core. To examine the <TEX>$ {B}$</TEX>– <TEX>$ {H}$</TEX> curve and the iron loss of a core affected by the manufacturing process, a slinky-laminated surface-mounted permanent magnet synchronous motor (SPMSM) was proposed as an analysis model. The magnetic properties of the slinky-laminated core and the stacked core were compared as the results of material experiments, using the proposed motor core. With the examined material data, the iron loss of the slinky-laminated SPMSM was investigated via the finite-element method (FEM). Finally, the proposed motor was subjected to a no-load test and a mechanical loss test. Based on the test results, the actual iron loss of the motor was obtained through loss segregation and was then compared with the FEM results to verify the validity of the material experiment and loss analysis methods.</P>

Enhanced UV-Visible Absorbance Detection in Capillary Electrophoresis Using Modified T-Shaped Post-Column Flow Cell

Lim, Kwan-Seop,Kim, Su-Hyeon,Hahn, Jong-Hoon Korean Chemical Society 2002 Bulletin of the Korean Chemical Society Vol.23 No.2

The construction of the T-shaped post-column flow cell has been changed to enhance the practicability as a UV-visible absorbance detector for capillary electrophoresis. In this new design, a rectangular cube-shaped inner structure is employed, which completely fits the outer rectangular tubing. This arrangement has greatly facilitated the fabrication of the T-cells. In addition, the volume for the auxiliary flow has been dramatically reduced down to 300 ${\mu}L$, and its volume flow rate is optimized at 4.2 ${\mu}L$/min. The short optical path length in the sheath flows (500 ${\mu}m$ on each side) minimizes background absorption, and thus enhances its performance in low-UV wavelengths. We have optimized the auxiliary flow rate at 50 ${\mu}m$/s, so that migration times are insensitive to the flow rate. This optimization has improved repeatabilities in migration times and peak heights. A double-beam detection scheme using a pair of photodiodes is employed to increase the signal-to-noise ratio.

A Case of Neurocysticercosis in Entire Spinal Level

Lim, Byung-Chan,Lee, Rae-Seop,Lim, Jun-Seop,Cha, Kyu-Yong The Korean Neurosurgical Society 2010 Journal of Korean neurosurgical society Vol.48 No.4

Cysticercosis is the most common parasitic infection affecting the central nervous system. Spinal neurocysticercosis (NCC) is very rare compared with intracranial NCC arid requires more aggressive management because these lesions are poorly tolerated. The authors report a case of intradural extramedullary cysticercosis of the entire level of spine with review of the literature.

Parametric study of propeller boss cap fins for container ships

Lim, Sang-Seop,Kim, Tae-Won,Lee, Dong-Myung,Kang, Chung-Gil,Kim, Soo-Young The Society of Naval Architects of Korea 2014 International Journal of Naval Architecture and Oc Vol.6 No.2

The global price of oil, which is both finite and limited in quantity, has been rising steadily because of the increasing requirements for energy in both developing and developed countries. Furthermore, regulations have been strengthened across all industries to address global warming. Many studies of hull resistance, propulsion and operation of ships have been performed to reduce fuel consumption and emissions. This study examined the design parameters of the propeller boss cap fin (PBCF) and hub cap for 6,000TEU container ships to improve the propulsion efficiency. The design parameters of PBCF have been selected based on the geometrical shape. Computational fluid dynamics (CFD) analysis with a propeller open water (POW) test was performed to check the validity of CFD analysis. The design of experiment (DOE) case was selected as a full factorial design, and the experiment was analyzed by POW and CFD analysis. Analysis of variance (ANOVA) was performed to determine the correlation among design parameters. Four design alternatives of PBCF were selected from the DOE. The shape of a propeller hub cap was selected as a divergent shape, and the divergent angle was determined by the DOE. Four design alternatives of PBCF were attached to the divergent hub cap, and the POW was estimated by CFD. As a result, the divergent hub cap with PBCF has a negative effect on the POW, which is induced by an increase in torque coefficient. A POW test and cavitation test were performed with a divergent hub cap with PBCF to verify the CFD result. The POW test result showed that the open water efficiency was increased approximately 2% with a divergent hub cap compared to a normal cap. The POW test result was similar to the CFD result, and the divergent hub cap with the PBCF models showed lower open water efficiency. This was attributed to an increase in the torque coefficient just like the CFD results. A cavitation test was performed using the 2 models selected. The test result showed that the hub vortex is increased downstream of the propeller.

New application of poly(butylene succinate) (PBS) based ionomer as biopolymer: a role of ion group for hydroxyapatite (HAp) crystal formation

Lim, Jung Seop,Kim, Jong Hoon Springer-Verlag 2009 JOURNAL OF MATERIALS SCIENCE - Vol.44 No.23

Supramax Bulk Carrier Market Forecasting with Technical Indicators and Neural Networks

Lim, Sang-Seop,Yun, Hee-Sung Korean Institute of Navigation and Port Research 2018 한국항해항만학회지 Vol.42 No.5

Supramax bulk carriers cover a wide range of ocean transportation requirements, from major to minor bulk cargoes. Market forecasting for this segment has posed a challenge to researchers, due to complexity involved, on the demand side of the forecasting model. This paper addresses this issue by using technical indicators as input features, instead of complicated supply-demand variables. Artificial neural networks (ANN), one of the most popular machine-learning tools, were used to replace classical time-series models. Results revealed that ANN outperformed the benchmark binomial logistic regression model, and predicted direction of the spot market with more than 70% accuracy. Results obtained in this paper, can enable chartering desks to make better short-term chartering decisions.

Use of sofosbuvir in chronic kidney disease: Is it necessary?

( Tae Seop Lim ),( Sang Hoon Ahn ) 대한간학회 2017 Clinical and Molecular Hepatology(대한간학회지) Vol.23 No.4